Ya know its weird - some say they've no probs just popin' the pin out with a nail or whatever or even the wallyworld breaker, some say they struggle for hours with no luck at all - even with the proper tool.
I've done a coupla these chains now, both the kit supplied 415 and the domestic 41 equivalent (just a hair wider) and I tell ya what - for me there was no "just pop the pin out" as they were mushroomed over quite effectively.
I'm not sayin' people are wrong, I bet... no, I know
all of these chains are made a lil different lol The "solution" that'll work on any chain regardless of how stubborn is to grind on pin flush with the link, cut one side of the link (scrap side ofc), twist with a pair of pliers - and it'll pop right off every time.
While hammers are indeed an awesome tool - I do try to avoid using them... first anyway lol
You'll need to use the supplied master link to reconnect the chain, just make sure the clip is facing the right way when you reassemble it. If the link is at the top of the chain (going into the motor if you rolled the bike forward) the open end of the clip should face the back of the bike.
Good luck and happy riding